Power system operators are responsible for maintaining an instantaneous and continuous balance between supply and demand of power at transmission substations. This task is complicated by the increased presence of distributed energy resources (DERs), such as wind and solar generation, in the distribution system, which are fed by transmission substations. The unpredictable nature of these renewable energy sources leads to greater fluctuations in the amount of generated power available. Such fluctuations in generation capacity are present in addition to fluctuations in power demand.
To achieve a power balance in the presence of heightened volatility of energy resources, operators increase the use of reserve capacities, which are able to operate in load flowing mode. However, increasing power production by reserve units comes at the cost of reducing power production by more energy-efficient base-load generation units, reducing the environmental benefits of using renewable DERs.
Rather than relying on reserve units to act in load-following mode, there has been much interest on the topic of demand response, which adjusts loads in order to smooth out volatility in renewable generation capacity and power demand.
A variety of methods are known for reducing the load demands at specific periods through implementing demand response programs. For example, US 20110066300 provides a method for controlling load in a utility distribution network that initiates a shed event for a node in the distribution network by selecting premises associated with the node that are participating in a demand response program to reduce the load at the node to desired levels.
US 20100211443 utilizes demand response to reduce energy consumption by individual consumers by aggregating individual consumers, and providing feedback to such consumers regarding their energy consumption relative to other energy consumers in a group.
U.S. Pat. No. 8,068,938 describes a method for managing electrical demand on a power grid in response to electrical supply conditions which includes determining a first energy demand forecast using stored information, determining a first energy supply forecast based on a known energy production and transmission capacity, and comparing the first energy demand forecast to the first energy supply forecast. The method also includes transmitting at least one of an adjusted price signal and an electrical load shedding signal to a customer over a bi-directional communication system based on the comparison of the first energy demand forecast to the first energy supply forecast.
US 20020138176 provides means and methods for the automated aggregation and management of distributed electric load reduction. US 20090187499 provides a system, method and computer program product for providing demand response in a power grid. In one embodiment, the computer system can include a first module configured to store user profile data for a plurality of users in memory and wherein user profile data includes load shed participation data for at least some of the plurality of users, information identifying one or more load control devices associated with each of the plurality of users, and location data of a premises associated with the user. The system can include a second module configured to select a multitude of the users based, at least in part, on the load shed participation data of the profile data, a third module configured to transmit a first control message to a load control device of the selected users, wherein the control message comprises a request to reduce a load.
Most of existing methods are focused on how to reduce the peak demands and do not address how to smoothen the aggregated load curve at the substations to reduce the usage of reserve units. Therefore, there is a need for developing effective mechanism or techniques to reduce the substation load fluctuations.